POL6326
Evidence Grade C — Moderate human evidence. 14 published studies, 11 human. 9 registered clinical trials.
Balixafortide is a synthetic peptide that blocks the CXCR4 receptor, tested as a way to sensitise breast cancer tumours to chemotherapy. A promising Phase Ib trial showed a 30% response rate, but the pivotal Phase III trial (FORTRESS) was discontinued after an interim analysis showed it was unlikely to succeed. Its clinical development for breast cancer has been abandoned.
14 published studies: 11 human, 1 animal, 0 in-vitro, 6 reviews
Balixafortide is not approved. The Phase Ib trial (54 evaluable patients) in HER2-negative metastatic breast cancer showed a 30% objective response rate when combined with eribulin chemotherapy. However, the Phase III FORTRESS trial was discontinued after interim futility analysis showed it was unlikely to meet its primary endpoint.
Balixafortide's development trajectory illustrates the challenge of translating promising Phase Ib combination therapy results into Phase III confirmation. The compound's clinical development has been discontinued.
Balixafortide blocks the CXCR4/CXCL12 signalling axis, which cancer cells use to migrate, evade immune detection, and shelter in protective tissue niches. By disrupting this signalling, the compound is proposed to expose cancer cells to chemotherapy and immune attack. The Phase Ib results suggested this mechanism could enhance chemotherapy response rates.
Research suggests the Phase Ib trial (54 patients) in metastatic breast cancer showed a 30% objective response rate when combined with chemotherapy — an encouraging signal. However, the Phase III FORTRESS trial was stopped at interim analysis for futility, definitively ending the breast cancer programme. The disconnect between promising early-phase results and Phase III failure highlights the well-known challenge of single-arm early oncology data: small, uncontrolled studies can overestimate treatment effects. The developer is evaluating alternative indications including stem cell mobilisation and haematological cancers, but no viable clinical path has been established.
Phase I Study of Cosibelimab and Balixafortide in Metastatic Pancreatic Ductal Adenocarcinoma
Tumor-Targeted-NIR-II Fluorescent Molecular Probes for the Identification of Breast Cancer Tissue and SLN Metastatic Status
POL6326 (Balixafortide) Plus Nab-paclitaxel or Eribulin in Patients With HER2-negative Advanced Breast Cancer
Pivotal Study in HER2 Negative, Locally Recurrent or Metastatic Breast Cancer
CXCR4 Antagonism for Cell Mobilisation and Healing in Acute Myocardial Infarction (CATCH-AMI)
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